Master-key lock



(Model.)

D. K. MILLER.

MASTER KEY 1.00K.

u Pneus Mmmwf. mmm u. a

UNITED VSTATES PATENT OFFICE.

,DANIEL MILLER., OF PHILADELPHIA, PENNSYLVANIA.

MASTER-KEY Look.

f SPECIFICATION forming part of Letters Patent No. 244,759, dated July 26, 1881.

Application filed Noyember B, 1880. (Model.)

To alt/whom it may concern Beit knownv that I, DANIEL K. MILLER, a citizen of the United States, residing at Philadelphia, Pennsylvania, have invented certain Improvements in Master-Key Locks, ot' which the following is a specification.

The main object of my invention is to so construct a master-key lock that a much greaterthe cover-plate removed and the bolt retracted; Fi g.2, a view showing the action of the special key in operating the lock; Fig.3, a view show ing the action of a master-key in performing the same duty, Fig. 4, a view showing the bolt projected; Fig. 5, a side view of the bolt detached from the lock; Fig. 6, a detached perspective view of another part of the lock mechaniism, and Fig. 7 a view of a modification.

A is the casing of the lock; B, the bolt, and A D the tumblers, of which three are shown in the drawings, although greater number than this may be used, if desired. The bolt B slides longitudinally in the. case, and the tumblers are hung to a pivot pin, E, each of said tumblers being acted upon by a spring, F, and having two notches, a a', formed in its rear edge. These notches are so located in respect to the lower edges of the tumblers on which the keys act that the notches a will be brought into line by the special key G, and the notches a by the master-key G', vor the reverse of this may be. the case, if desired.

Instead of using but one stump on the shank of the bolt for both sets of notches, as usual, my improved lock has two stumps, mm', which, in the presentinstance, are in the form of projections on a dog, b, the latter being pivoted to the short arm of a bell-crank lever, d, hung to a pin on the lockcase. The long arm of the lever dis furnished with a projecting sprin g, e, which rests upon the stud carrying the pivotpin E, the tendency of this spring being to elevate the end of the long arm of the lever, and thereby press the stumps m m firmly against the rearedges of the tumblers, as shown in Figs. 1 and 4. When the bolt is retracted and the tumblers are down, as shown in Fig.

1, the long arm of the lever d occupies apposition in a notch,f, iu the upper edge of the shank of the bolt B, and prevents the projection of said bolt. When the tumblers are acted upon by the special key G of the lock the notches a of the tumblers are brought into line with each other and into the path of the stump m, lwhich enters the notches, as shown in Fig. 2,and thereby allows such amovement of the lever d that the end of the long arm of the latter is freed from the notch f and theprojection of the bolt by the key is permitted. The same movement of the lever d takes place on the operation ofthe tumblers by the ni aster-key G'; but in this case the notches a of the tumblers are brought into line with each other and into the path of the stump m', which enters the notches, as shown in Fig. 3. When the bolt has been projected, either by the special key Gr or masterkey G', a notch, g, in the upper edge of the shank of the bolt, isbrought into the path of the end of the long arm of the lever d, by which means the descent of the tumblers, under the action of the spring F, is permitted,the inclinednotches in the tumblers forcing out the stump, and thus causing the pivot of the dog b to move rearwardly, the end of the long arm of the lever d entering the notch g of the bolt, as shown in Fig. 4. Ithus overcome an objection to that` class of masterkey locks in which a stump on the bolt enters notches in the tumblers when the latter are adj usted by the key and remains therein while the boltis projected, thus retaining the tumblers in their elevated positions, so that by means of a sectional key introduced into the lock the relative positions of the tumblers can be readily determined and a false key for the lock constructed. l

In my improved lock the tumblers are not confined by the stump, except during the actual movement of the bolt as the latteris being retracted or projected.- Pressure npon the end of the bolt when the latter isprojected causes such a retention of the long arm of the lever d as to prevent the elevation of the latter by the action of the spring e, the stumps m m IUD being thus prevented from entering the notches in the tumhlers, so that any attempt to ascertain the position of said notches by manipulating the tumblers while longitudinal pressure is exerted upon the bolt is eftectually prevented.

In an ordinary masterkeylock havinga single stump, both the special-key notch and the master-key notch have to be formed in the edge of the tumbler, Within the limits of the travel of said edge; and, as this space is necessarily contracted, the ,number ot' different combinations of special-key notches which can be made is correspondingly limited. By the use of two stumps, however, I am enabled to separate the speciatkey notches from the master-key notches to any extent desired, and can thus devote to the formation of the special-key notches alone a space equal to the travel of the edges of the tulnblers in which said notches are made, thus greatly increasing the number of diiferent combinations attainable.

Different combinations of master-key notches may also be made Without interference with the special-key notches, so that with, say, a thousand locks, each requiring a special key diifering from those of the others, there may be but one master-key for the entire number of locks, or there may be a number ot' different 1naster-keys,earh controlling but a limited number of locks.

In carrying out my invention,the particular methods of construction before described, and shown in Figs. 1 to 6 of thedrawings, need not be adhered to in all cases. For instance, in

Fig. 7 I have shown a inodiiication in which sliding tulnblers take the place of the pivoted tumblers D. The notched tumblers and double stump may also be used in connection with locks of the character shown in my Patent No. 143,831, October 21, 1873; and in some cases the dog b maybe carried by a sliding plate instead ot' by a lever, or a central pin 011 the dog itself may be adapted to the retainingnotches in the bolt. The two notches in the boltshank may also be used with advantage in connection with a retaining device having but one stump.

I claim as my invention- 1. The combination of the bolt and the notched tumblers of a master-key lock with two stumps independent of the tumblers, one stump being adapted to the notches brought into line by the special key, and the other to the notches brought into line by the masterkey, and with devices whereby the entrance ot' either stump into its notches is caused to release the bolt, as set forth.

2. The combination of the bolt and the notched tnmblers of a master-key lock,a dog, l), having two stumps, m m', formed on or secured thereto,andaboltretainingandreleasing device, to which said dog is pivoted, said stump m heilig adapted to the special-key notches, and the stump m to the master-key notches, all substantially as specified.

3. rlhe combination of the notched tumblers, the locking-bolt B, having t\vo notches,fand g, and a stump-carrier having a lug or projection adapted to either of the notchesf and g ot' the bolt, as specified.

t. The combination of the notched tum blers, the locking-holt B, having two notches,f and g, and a stump-carrier consisting of a bellcrank lever, (l, one arm of which has a lug or projection adapted to either of said notches in the bolt, as set forth.

In testimony whereof I have signed my name to this specification in the presence ot' two subscribing witnesses.

I). K. MILLER.

\Vitnesses:

J AMEs F. ToBIN, HARRY SMITH. 

